Modern vehicles come equipped with an onboard computer diagnostic system (OBD II) that monitors your vehicle’s operations. The OBD II system monitors emissions control systems. That means the monitors can detect anything from a loose fuel cap to a clogged catalytic converter. An illuminated check engine light means that the driver should have the vehicle checked as soon as possible; a flashing check engine Iight means that the driver should park and shut off the vehicle immediately - before serious engine or emissions system damage
